Tube bending machine



H. SCHMIDT TUBE BENDING MACHINE Sept. 1, 1964 2 Sheets-Sheet 1 FiledNov. 19, 1962 l N VEN TOR. flaws 50/121102" Sept. 1, 1964 H. SCHMIDTTUBE BENDING MACHINE 2 Sheets-Sheet 2 Filed Nov. 19, 1962 0 WWW WM? 15%}United States Patent 3,146,818 TUBE BENDING MACHINE Hans Schmidt,Aurora, Ill., assignor to Pines Engineering C0,, Inc, Aurora, 111., acorporation of Illinois Filed Nov. 19, 1962, Ser. No. 238,646 7 Claims.(Cl. 153-40) The present invention relates to improvements in bendingmachines and is particularly concerned with the novel construction andassembly of such a machine in which is provided means of novelconstruction for selectively locking the bending or pressure die holderto the bending form for joint rotation during a bending operation.

More particularly, the exemplary bending machine herein disclosedincludes a base structure upon one end of which is mounted a rotatablebending form, a rigid clamp die holder, and a bending or pressure dieholder. The latter is mounted for free rotation about the axis of thebending form and it embodies novel hydraulic pressure actuated means forlocking the pressure die holder and the bending form together for jointrotation during a bending operation. Such locking and joint rotation isdesired to avoid distortion to the work piece as so often occurs whilethe work piece is being wrapped around a stationary bending form. In thepresent disclosure, the pressure die holder can be unlocked and returnedto its initial position after completion of a bending operation withoutreturning the bending form to its initial position. Because of thisstructure, the bending form is rotatably driven through and by movementof and in harmony with rotation of the pressure die holder, thuseliminating all slippage or drag during a bending operation.

It is therefore an object of the invention to provide a bending machinehaving the structural characteristics outlined hereinabove.

Another object of the invention is to provide, in a bending machine,novel means for selectively locking the movable pressure die holder tothe bending form during a bending operation.

Another object is to provide a pressure die holder with novel means tolock it to a bending form.

Another object is to provide novel hydraulically actuated lock means.

Another object is to provide a machine having the features describedhereinabove which is not expensive to manufacture, is simple in itsconstruction and operation, is easy to operate, and is very efficientand effective for the purpose intended.

With the foregoing and such other objects in view, which will appear asthe description proceeds, the invention consists of certain novelfeatures of construction, arrangement and combination of partshereinafter fully described, illustrated in the accompanying drawings,and particularly pointed out in the appended claims, it being understoodthat various changes in form, proportion, size and minor details of thestructure may be made without departing from the spirit of theinvention.

Referring to the drawings in which the same characters of reference areemployed to identify corresponding parts:

FIG. 1 is a plan view of one end of a bending machine, showing thebending form, stationary clamp die holder, and rotatable bending orpressure die holder, the latter being shown in bending position inbroken lines;

FIG. 2 is an enlarged vertical sectional view taken substantially online 2-2 of FIG. 1, and showing the bending form locked to the pressuredie holder for rotation therewith;

FIG. 3 is a fragmentary view similar to FIG. 2, and partly in elevation,showing the parts in unlocked position; and,

FIG. 4 is a detail sectional view taken on line 4-4 of FIG. 2.

Referring to the accompanying drawings, the bending machine illustratedis of a type used for bending tubular, bar or rod stock. The machinecomprises essentially a base frame structure 11 including, at one end, anose housing 12 in and about which a bending form 13 and pressure dieholder 14 are mounted for rotation. The machine also includes a rigidclamp die holder 15 arranged rearwardly of the nose housing whichcarries clamp dies movable into and out of engagement with a work piece16, illustrated in FIG. 1 by a light broken line, being fedlongitudinally along the machine base toward and beyond the nose housing12.

As is well understood, a work piece 16, such as a length of tubing orbar or rod stock, is fed into position against the channelled perimeterof the bending form 13 whereupon the pressure or bending die 17,illustrated in FIG. 2 only, is brought into tight clamping engagementwith the workpiece 16 upon manipulation of the toggle assembly 18generally shown in FIG. 2. The pressure die 17 then is rotated about theaxis of the bending form 13, as by means and in a manner to be describedpresently, so as to wrap the work piece around said bending form. Duringthis rotational movement of the pressure die, the support holder 14 islocked to the bending form. or its mounting so as to rotate the bendingform therewith. Upon completion of the bending operation, the pressuredie holder is unlocked and said structure is freed from the bending formmounting so as to be free to be returned to its initial position withoutcarrying the bending form therewith.

More specifically, the nose housing 12 provides a journal in which boththe bending form 13 and pressure die holder 14 are mounted. As shown,the nose housing 12 is hollow and has upper and lower walls 19 withvertically aligned apertures through which a bearing sleeve 21 extendsand which is journalled therein for free rotation in anti-frictionbearings 22. A trunnion 23 is freely journalled in and extends throughbearing sleeve 21 and is formed on its upper end with a disc 24 having atangential flat area 25 (FIG. 1) on its perimeter. This area is formedwith a radial notch 26 for a purpose to be explained presently. Thebending form 13 is mounted on top of said disc 24 and is secured firmlythereto for rotation with trunnion 23 as by means of a stud 27 and nut28. The bending form 13 may be removed upon removal of nut 28 so as tobe replaced by a bending form of a different size.

The bearing sleeve 21 has welded or otherwise secured firmly to it,preferably at its upper end as at 29, one end of an arm 31 comprising apart of the bending die holder 14. As shown, the bending die holder 14is substantially rectangular in shape and it has, along the upper edgeof its vertically depending reinforcing webs 32, a U-shaped trough 33that is substantially square in section. The trough is closed at itsfree end by an end wall 34 which may be secured thereto as by screws 35.A slide plate. 36 is seated over the open top of the U-shaped trough andit has an integral cylindrical body 37 depending into said trough. Thecylindrical body 37 is closed at one end by an end wall 38 and its otherend is open to receive therein a cylinder assembly 39 now to bedescribed.

This assembly 39 comprises a cylindrical wall 41, having an integral endwall 42 that is abutted against and secured to the end wall 38 of body37 as by screws 43. The other end of said cylindrical wall 41 mounts acap plate 44, secured to said wall by screws 4-5, including a packinggland 46. A piston rod 47 extends through the packing gland as shown,and mounts a piston 43 within cylindrical wall 41 which, with its endwall 42 and cap plate 44, constitutes a cylinder for said piston.

The projecting end of said piston rod is anchored firmly in the troughend wall 34. The piston rod has an axial passageway 49 to which isconnected a fluid line 51 leading from any suitable fluid pressuresource not shown.

The slide plate 36 has an end portion extending beyond the cylinder endWall 42, and it has a substantially rectangular tooth or lug 52 on itsfree end. This lug 52 is adapted, when fluid is admitted into cylinder41, to engage in the radial notch 26 for locking the pressure die holder14 to the bending form for rotation in unison. When negative pressure ispresent within the cylinder, the lug 52 is withdrawn from notchengagement so that the pressure die holder 14 may be rotated about itsaxis independently of the bending form 13.

The plate 36 has, at its end remote from lug 52, an upstanding boss 53mounting an adjustable stop screw 54, and the top surface of said platehas a longitudinally extending slot 55 in which the pressure die toggleassembly 18 is mounted. This assembly comprises a backup block 56 and aslide block 57 connected by a manually actuated toggle linkage 58. Theslide block 57 mounts the pressure die 17 that is adapted to cooperatewith bending form 13 for bending a work piece 16 about the latter whenthe pressure die is carried through an are about the axis of the bendingform as, for example, from the full line position to the broken lineposition illustrated in FIG. 1.

Rotation of the pressure die holder 14 is effected through the provisionof a sprocket 62 on bearing sleeve 21 which has a chain 63 (FIG. 1)engaged therewith and adapted to be driven selectively when bendingmovement or return movement of the holder is required. The drive meansfor chain 63 is conventional and is not shown.

It should be evident that novel means and apparatus has been providedfor locking the pressure die holder 14 to the bending form and that suchmeans is positive in its operation. Also, when a bending operation iscompleted, the pressure die holder can be unlocked and returned to itsinitial position without reverse rotation of the bending form so as tominimize frictional resistance to the return of the parts to normal andpossible distortion of the bend formed in the workpiece.

As many possible embodiments may be made in the invention and as manychanges might be made in the embodiment above set forth, it is to beunderstood that all matters hereinbefore set forth or shown in theaccompanying drawings are to be interpreted as illustrative and not in alimiting sense.

What I claim and desire to secure by Letters Patent of the United Statesis:

1. A bending machine comprising a base structure, a bearing sleevejournalled for rotation in said base structure, a pressure die holderintegral with and extending radially from said sleeve, 21 trunnionjournalled in said sleeve, a bending form on said trunnion and rotatabletherewith, and disengageable means on the pressure die holder to locksaid holder to the trunnion for rotation therewith.

2. A bending machine comprising a base structure, a bearing sleevejournalled on an axis therein, a pressure die holder integral with andextending radially from All said sleeve, said sleeve and pressure dieholder being rotatable in unison about said axis, a trunnion journalledfor free rotation in said sleeve, a forming die integrally connectedwith said trunnion, a pressure die mounted on the pressure die holderfor cooperation with the forming die to bend a workpiece when thepressure die holder is rotated in one direction about its axis, andmeans to lock the pressure die holder and trunnion for rotation of thebending form during rotation of the pressure die holder in said onedirection.

3. A bending machine comprising a base structure having a nose housingat one end, a bearing sleeve journalled on a vertical axis in said nosehousing, a pressure die holder integral with and extending radially fromsaid sleeve, a trunnion journalled in said sleeve, a bending form onsaid trunnion and rotatable therewith, and disengageable means on thepressure die holder to lock said holder to the trunnion for rotationtherewith.

4. The bending machine recited in claim 3, in which the means to lockthe pressure die holder comprises fluid pressure actuated means on thepressure die holder engageable with said trunnion.

5. A bending machine comprising a base structure having a bearing sleevejournalled on an axis therein, a pressure die holder integral with andextending radially from said sleeve, means to rotate said sleeve andpressure die holder about said axis, a trunnion journalled for freerotation in said sleeve, a forming die integrally connected with saidtrunnion, a pressure die mounted on the pressure die holder forcooperation with the forming die to bend a workpiece when the pressuredie holder is rotated in one direction about its axis, and means to lockthe pressure die holder and trunnion for rotation of the bending formduring rotation of the pressure die holder in said one direction.

6. The bending machine described in claim 5, in which the lock meanscomprises a hydraulically actuated latch carried by the pressure dieholder.

7. A bending machine comprising a base structure having a bearing sleevejournalled on an axis therein, a pressure die holder integral with andextending radially from said sleeve, means to rotate said sleeve andpressure die holder about said axis, a trunnion journalled for freerotation in said sleeve, a forming die integrally connected with saidtrunnion, a slide plate mounted on the pressure die holder, a pressuredie mounted on said slide plate, means to slide said plate in thedirection of the bending form, and means on said slide plate engageablewith the trunnion for locking the pressure die holder to said trunnionfor rotating the bending form and pressure die holder in unison.

References Cited in the file of this patent UNITED STATES PATENTS1,264,097 Lichtenberg Apr. 23, 1918 2,223,015 Hathorn Nov. 26, 19402,444,596 Doucette July 6, 1948 2,933,565 Klamm May 31, 1960 OTHERREFERENCES Pines Engineering Co., Inc., American Machinist, vol. 96,Issue 12, page 63, pub. date: June 23, 1952.

1. A BENDING MACHINE COMPRISING A BASE STRUCTURE, A BEARING SLEEVEJOURNALLED FOR ROTATION IN SAID BASE STRUCTURE, A PRESSURE DIE HOLDERINTEGRAL WITH AND EXTENDING RADIALLY FROM SAID SLEEVE, A TRUNNIONJOURNALLED IN SAID SLEEVE, A BENDING FORM ON SAID TRUNNION AND ROTATABLETHEREWITH, AND DISENGAGEABLE MEANS ON THE PRESSURE DIE HOLDER TO LOCKSAID HOLDER TO THE TRUNNION FOR ROTATION THEREWITH.